Lubricant



I Patented Get. 28, 1941 LUBRICANT Peter A. Assei'i', Cleveland, Ohio, assignor to The Lubri-Zol Corporation, Wickliile, Ohio, a cornotation of Ohio No Drawing. Application July 28, 1941,

Serial No. 404,361

14 Claims.

This invention relates as indicated to improved lubricants and more particularly to compounded lubricants which comprise a mineral lubricating oil base, the properties of which affecting its use as a lubricant will be improved by the inclusion therein of an addition agent.

Refined mineral lubricating oils while useful over a wide range of applications, are, nevertheless, not satisfactory for certain uses either on account of their tendencyto deteriorate or on account of their inability to withstand high film pressures or otherwise perform the lubricating function required.

-It is a principal object of this invention, therefore, to provide a compounded lubricant which while including a mineral oil base has properties which cannot be secured by the use of mineral oil alone.

Other objects of the invention will appear as the description-proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principal of the invention may be employed.

Broadly stated, the compounded lubricating composition of this invention may be defined as comprising a major amount of a hydrocarbon oil, such as mineral lubricating oil, and-a minor amount of a zinc salt of an acidic reaction product obtained by reaction phosphorus pentasulphide with a cycle-aliphatic alcohol.

In the foregoing broad statement of this invention the addition agent has been defined in terms of its mode of preparation and desirably and necessarily so 'on account of the difficulty in a more precise identification of the molecule characterizing the addition agent. As a matter of fact the addition agent is probably a mixture of different constituents and it is for this reason that the same is best defined, as above indicated,

in terms of its mode of preparation. The addition agent may be prepared as indicated by reacting phosphorus pentasulphide with a cycloaliphatic alcohol in the preparation of an intermediate acidic reaction product and the zinc salt then prepared of such acidic reaction product.

Alternatively, the final product may be prepared in a single step or in concurrent steps by reacting together .phosphorus pentasulphlde the alcohol, and zinc oxide. In this case, it is probarranged substantially in the order of preference.

Methyl cyclohexanol Ethyl cyclohexanol Propyl cyclohexanol Amyl cyclohexanol Sterols, e. g. Cosmol" (a cyclic alcohol derived from wool-fat) Cyclohexanol Methyl cycloheptanol Methyl cyclopentanol cycloheptanol Cyclopentanol It is not necessary that the cycloaliphatic alcohol used for this purpose be a pure compound. It may consist of a mixture of cycloaliphatic alcohols and such mixtures are often particularly advantageous. An example of such material is themixture of alcohols resulting from the hydrogenation of commercial cresol. The methyl cyclohexanol referred to hereafter is the product thus obtained. A mixture of alkylated cyclohexanols consisting principally of ethyland propyl cyclohexanols has also been found particularly suitable for this purpose.

The cycloaliphatic alcohols which contain the cyclohexane nucleus, for example cyclohexanol and the alkylated cyclohexanols, are particularly useful cycloaliphatic alcohols for my purpose because they are commercially available and proguce a product which has advantageous properies.

Of the cycloaliphatic alcohols in general those are preferred which have a total of less than ten carbon atoms. cohols are particularly suitable. In this case,it is best to have the alkyl group contain less than six and preferably less than four carbon atoms.

I Since aspeciflc example of the addition agents of the present invention which has been found of especial utility is the zinc salt of the acidic reaction product obtained by reacting phosphorus pentasulphlde with methyl cyclohexanol. the

details of the manufacture of such material will be given as illustrative of the-mode of manufcture of the similar addition agents comprised within the broad statement of the invention,

The alkylated cycloaliphatic al- This process may be divided into two parts, i. e.

(a) The preparation of the acid ester, and (b) The preparation of the metallic salt of such acid ester.

(a) PizaPARATIon OF THE Acrn ESTER Five moles of methyl cyclohexanol and one mole of P235 were mixed with an amount of benzene equal in volume to the amount of cyclohexanol and placed in a flash equipped with a reflux condenser, a thermometer and a mechanical stir. The flask was placed in a water bath at approximately 100 C. and refluxed for four hours. The batch was then cooled to about 60 C. and washed once with an equal volume oi water at 60 C. The benzene was removed from the wash material by distillation at atmospheric pressure. A typical batch in the preparation of the acid ester in the mode above defined was as follows: 7 Wt. of methyl cyclohexanol grams 500 Moles of methyl cyclohexanol 4.39 Weight of P255 grams 195.5 Moles of P2S5 .88 C. c. of benzol used as solvent 500 C. c. of 60 0. H20 used in washing 1000 Weight of product grams 616 Temp. of reaction, C:

Bath temp C 100 Vapor temp C 80 Time of reaction hours 4 It is believed that the reaction between phosphorus pentasulphide and the alcohol produces a mixture of compounds of the type represented by acid thiophosphate esters. For example:

R is the cycle-aliphatic radicle derived from the alcohol R is hydrogen or R The final product, if this assumption is correct,

would then consist of the salts derived from the acid ester by replacing the replaceable hydrogen of such esters with zinc.

(b) PREPARATION or THE Ma'rALLIo SALT First method The acid ester resulting from step (a) above was mixed with enough water to make a 15-20% mixture. This solution was made neutral to phenolphthalein with 30% aqueous caustic. The acid was neutralized at 8090 C. To the sodasalt solution was added an aqueous solution of zinc chloride. The reaction mixture was stirred at 80-90 C. for fifteen minutes, and then allowedto settle. The time required for the separation of the water from the salt was about fifteen minutes. The water was then poured 011 and the zinc salt dissolved in twice its volume of benzene. The water and benzene were removed by vacuum distillation at about seven inches vacuum. The maximum temperature 01 distillation was 100 C. A typical batch in the preparation of the zinc salt of the reaction product of phosphorus pentasulphide and methyl cyclohexanoi was as follows:

Grams of salt obtained 980 Per cent yield 89.5 Time of reaction between NaOH and acid minutes 15 Time of reaction between Na salt and ZnCi-z minutes 15 Temperature 01' reaction, C:

NaOH+acid -90 Na salt+ZnClz 80-90 C. c. of benzol used for dehydration 2000 Temperature of dehydration "C maximum Pressure of dehydration inches oi! H8" '23 Second method Grams Methyl cyclohexanol 865 Phosphorus pentasulphie 333 Zinc oxide 100 The methyl cyclohexanol and zine oxide are placed in a container and heated to F. Then the phosphorus pentasulphide is added in finely divided form so that it will pass a 40 mesh screen. The phosphorus pentasulphide is added over a period of about 40 minutes so that the temperature does not exceed 212 F. The temperature is then raised to 320 F. over a period of one hour and maintained at that temperature for an additional one-halt hour. The yield of product is 1167 grams, and may be:

(a) dissolved in an equal weight of mineral oil and filtered hot after the addition of 2% by weight of a filter aid such as Filtrol; or

(b) dissolved in an equal weight of benzol, filtered, and the benzol removed by evaporation under vacuum.

Third method The materials and the amounts are the same in this method as in the second method. The methyl cyclohexanol and phosphorus pentasulphide are mixed in a flask and maintained at a temperature of 212 F. by means of a water bath for seven hours. The zinc oxide is then added. and the temperatures raised over a period of one hour to 320 F., and maintained at that temperature for one hour. The yield is 1170 grams, and the final solution and purification may be the same as for the second method.

Fourth method Pounds Methyl cyclohexanol 2975 Phosphorus pentasulphide 1137.5 Zincoxide 391 temperature maintained for nine hours. Three thousand pounds of a neutral oil are added together with 2% of filter aid, and the solution is filtered at a temperature of about 200 F. The

yield of product. exclusive of the oil, is 8800 pounds.

Specific examples of addition agents contemthe lubricant tested, its comparison with an untreated base oil both as to physical properties and performance in the engine tests.

lated for use in this invention are given in Ta 3 Table A below with an indication oi. the percentagcs of the various elements found therein m g Composition by actual analysis.

T A 1 Untreated GAE ill naphthenic motor oil having a V. I. oi 5. 1 2 Exam le l+ rincsa lt oithe reaction product OiPsSsWith Exam me cy o exano 07 the "motion P1109- 3 Exampn 1+l7 sine salt of the reaction product of P S; t}: pr fv o m with amyl clohcxanol.

' 4 Example 11-36 zinc salt of the reaction product oi ms.

with my clohexanol. Pam m 5 un r i sa ag solevbent refined Mid-Continent motor o a go o a Ziri: methyl cyclohex Ps5s 14.6 7.7 7. 5 6 25 1? t??? l gl f the reaction product 01 P18.

me y cy 0 exam :III: 23: i sii i l t j fi ff??f: 2%: 7 Example 5+ 9 lino salt of the reaction product oi P15] .1 Zinc borneol ms 11.0 6.00 c.4o mm? cyclohomolz cyclohemnol 5 3 3.95 5. 8 liralliilpam zinc salt 0! the reaction product oi P18; 9 Untrvzabteduifanxntiori slly lagged SAE Pennsylvania mo to a o Representative examples of lubricating 00 10 Example iH-l% sine salt oi the reaction product oi ms. positions of the present invention were tested 20 3 gg w g ggg motion d ct P s by means of a 2% H. P. single-cylinder, liquidg'gg g g P cooled, four cycle gasoline engine, rated at 1800 Tam C Engine tests at- 30 hours: I

Piston ratin D B A- A D 13+ A B- D A- B+ Number oi r gs stuck 0 0 0 0 0 0 0 0 0 0 0 Percent iilling oi oil ring slots. 30 0 0 0 0 0 0 0 0 0 60 hBearing loss in mgs l2 6 10 82 25 10 ii 15 8 7 13 ours: a Piston rating D C- 3+ A D B A- 0+ D B+ B Number oi rings stuck 1 0 0 0 0 0 0 0 2 0 0 Percent flllin oi oil ring slots. 90 5 0 0 0 0 0 0v 85 0 0 Bearing loss mgs 60 l2 i6 52 09 M 10 14 13 12 23 90 hours:

Piston rating O A- D 3- 3+ C B- 13+ Number oi rings stuck 0 0 1 0 0 0 0 0 Percent filling oi oil ring slots. 10 0 0 0 0 0 0 0 Bearing loss inmgs 10 63 107 ill 14 16 17 20 hours:

Piston rating A- B A- C- C B Number of rings stuck 0 0 0 0 0 0 Percent iilling oi oil ring sl 0 0 0 0 6 5 Bearing loss in mgs 67 87 Z) 24 22 38 150 hours:

Piston ratin 3- 3+ O 13 Number oi rings stu 0 0 0 0 Percent filling of oil 0 0 5 5 Bearing loss in mgs 36 22 27 38 Drain analysis:

Percent vis. increase... 26. 5 28. 2 42. 0 31.8 as. 0 57. 5 Com carbon residue. 73 1.06 1. 13 1. 39 1. 84 2. 27 N aphtha insoluble... 9. 2 1. 6 4. 2 3. 5 l. 4 8. 6 Acid number 22 37 52 28 26 64 Almen film strength 4 10 11 4 6 9 R. P. M. The procedure used was as follows:

The engine was loaded by means of a fantype Coolant temperature ..F 345 Oil temperature F... 225 Air fuel ratio 12.7:1

The engine was stopped at 30 hour periods for inspection of piston, piston skirt, piston rings. connecting rod bearings, etc. The engine was equipped with removable connecting-rod bearings consisting of lead-bronze with a steel backing. These hearings were weighed at the beginning of the test and at each 30 hour inspection period. Before each new test, the engine was thoroughly cleaned and equipped with new piston, piston rings and with new connecting rod bearings.

In the following Table B will be found a tabulation of several lubricating compositions of the present invention and in following Table C will be found a tabulation of the characteristics of The zinc salts produced in accordance with the several modes outlined hereinbefore are all new compositions of matter and are being claimed as such.

One oi the principal uses of these zinc salts is in lubricating compositions for the purposes previously explained, and, in the manufacture ci a finished composition for use as a lubricant in the crank cases of internal combustion engines, the oil base will be preferably a highly-refined mineral lubricating oil. The range of viscosity for such oil may be from about to about 1000 seconds Saybolt Universal at 100 F. or from about 20 to about 100 seconds Saybolt Universal at 210 F. The preferred range of viscoslties for the oil base are from about to about 750 seconds Saybolt Universal at 109 F. or from about 40 to about '15 seconds Saybolt Universal at 210 F.

For certain uses the oil base will be preferably a high V. I. 0111 Generally for such uses the oil base should have a V. I. of at least 50 and preferably at least 85 (Dean and Davis System).

The concentration of the zinc salt in the finished lubricant will be largely determined by the particular use for which the composition is designed and the particular characteristics of the base oil or base composition to which they are added. In general, in compounded lubricating oils useful in Diesel engines, the concentration of these zinc salts will range from about .l% to about 4%, and preferably from .5% to 2.5%.

One of the particular uses of the zinc salts of my invention is in lubricating compositions which also contain so-called detergents, particularly of the metal-containing type. Among the detergents with which these zinc salts may be used in combination are the metal phenates, and especially the alkaline earth metal phenates.

Although the addition agents contemplated hereby have a certain degree of detergent action,

particularly in certain types of oils, when used as the sole addition agent, highly advantageous results may be obtained by using these addition agents with others, notably other oil-soluble organic metal compounds which, themselves, effeet a higher degree of detergency when used in hydrocarbon oils. Examples of such organic metal compounds are the oil-soluble salts of Organic acids produced by oxidation of petroleum fractions Naphthenic acids Fatty acids I-Ialogenated fatty acids, such as dichlor stearic acid Aromatic acids such as phenyl stearic acid and chlorphenyl stearic acid Sulphonic acids, e. g. sulphonic acids derived from petroleum Substituted phosphorus acids containing an organic substituent, e. g. the aliphatic, cycloaliphatic, and aromatic acid esters of phosphoric acid thio phosphoric acids, phosphorous acid and thio phosphorous acids The oil-soluble metallic phenates may also be used, such as those derived from such phenolic compounds as:

Alkylated phenols such as cetyl phenol and lauryl phenol Esters of salicylic acid sucheas lauryl salicylate and cetyl salicylate Halogenated alkyl phenols and esters of phenolic acids such as lauryl chlorphenols and lauryl chlorsalicylate sulphides and polysulphides derived from phenol and alkylated phenols, such as di(tertiary amyl hydroxy-phenyl) sulphides dl(tertiary amyl hydroxy-phenyl) disulphides Specific examples of such detergent addition agents are the following:

Calcium naphthenate Cobalt naphthenate Aluminum naphthenate Aluminum chlorphenyl stearate Aluminum cetyl phenate Calcium oleate Calcium dichlor stearate Cobalt dichlor stearate Calcium phenyl stearate Calcium chlorphenyl stearate Calcium cetyl phenate Calcium lauryl phenate Magnesium phenate of lauryl salicylate Calcium lauryl chlorphenate Magnesium phenate of lauryl chlorsalicylate Calcium phenate of di(tertiary amyl hydroxyphenyl) sulphide Calcium salt of mono-cetyl phosphate Calcium salt of di-cetyl phosphate Calcium salt of di-lauryl phosphate Aluminum sait or mono-cetyl phosphate Aluminum salt of di-cetyl phosphate Calcium salt of mahogany acids (petroleum sulphonic acids) Barium salt of mahogany acids Sodium salt of mahogany acids Chromium salt of mahogany acids Cobalt salt of mahogany acids The zinc salts of this invention may advantageously be used with detergents comprising combinations of oil-soluble metallic compounds. Examples of such combinations are:

(a) The combination of a metallic phenate with a metallic salt of a substituted phosphorus acid containing an organic substituent.

(b) The combination of an oil-soluble metallic alcoholate with an oil-soluble metallic salt of a substituted phosphorus acid containing an organic substituent.

(c) The combination of an oil-soluble metallic phenate with an oil-soluble metallic salt of a sulphonic acid.

(d) The combination of an oil-soluble metallic alcoholate with an oil-soluble metallic salt of a sulphonic acid.

Specific examples of combinations of this type are:

ExAuPLz I Per cent Calcim cetyl phenate .5

Calcium cetyl phosphate 25 Zinc salt of this invention A 5 Mineral lubricating oil Balance EXAMPLE 11 Per cent Calcium cetyl phenate Calcium cetyl phosphate 5 Zinc salt of this invention .75

Mineral lubricating oil Balance EXAMPLE III Per cent Aluminum butoxide 1 Calcium cetyl phosphate '75 Zinc salt of this invention 75 Mineral lubricating oil Balance EXAMPLE IV Per cent Calcium salt of mahogany acids (sulphonlc acid produced by the treatment of a petroleum fraction with fuming sulphuric acid) 1.2 Calcium salt derived from the alkylated phenol sulphide disclosed in U. S.

Patent No. 2,139,766 .8 Zinc salt of this invention .5 Mineral lubricating oil Balance EXAMPLE V Per cent Calcium salt of mahogany acids 1.2

Calcium salt of the condensation product of formaldehyde with amyl phenyl .5 Zinc salt of this invention .75 Mineral lubricating oil Balance EXAMPLE VI Per cent Calcium salt of mahogany acids 1.2 Aluminum butoxide ,1

Zinc salt of this invention .75

Mineral lubricating 01L Balance EXAMPLE VII Per cent Calcium salt of an acid produced by the oxidation of a fraction of a solventrefined parafl'inic mineral oil .7 Calcium salt derived from the alkylated phenol sulphide disclosed in U. S. Patent No. 2,l39,'766 Zinc salt of this invention Mineral lubricating oil Balance The foregoing specific examples, it will be observed, are in each instance lubricating compositions in which the mineral oil contains the zinc salt of this invention in combination with two other components. These have been given as representative not only of such three-component compositions, but also of two-component compositions which may be produced by the omission, from any of the above-named specific examples, of either one or the other of the two addition agents with which the zinc salt is shown in combination.

Additional specific examples of combinations in which the zinc salt is used with only one other detergent are as follows:

EXAMPLE VIII Mineral lubricating oil Balance EXAMPLE XII Per cent Cobalt chlorphenyl stearate .5 Zinc salt of this invention .75 Mineral lubricating oil Balance It will be noted that the addition agents of this invention contain, in a single compound, the combination of a cycloaliphatic radicle, a thiophosphate radicle, and the element, zinc. It has been discovered that this combination of constituents produces a material having a particularly desirable combination of properties for use in lubricating oil to be used in the crank cases of internal combustion engines under conditions of severe service. This combination of properties includes the following:

(1) High solubility in oils of high viscosity index;

(2) Detergent action or resistance to sludgeforming tendencies; and

(3) Controlled sulphur activity, contributing corrosion-inhibiting properties and resistance to the formation of acidic materials during oxidation. (4) Ability to increase film strength of the oil.

In the past, it has not been found possible to compound addition agents which would reduce corrosive tendencies, and the tendency to produce acidic materials during oxidation, without increasing the tendency to form deleterious deposits. By the use of the addition agents of this invention, however, the corrosive tendency and the formation of acidic materials are reduced while,

at the same time, reducing the tendency to form harmful deposits.

. Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

1, therefore, particularly point out and distinctly claim as my invention:

1. A lubricating composition comprising a major amount of a hydrocarbon oil and a minor amount of the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulfide with an alkylated cyclohexanol in which substantially all of the alkyl groups have less than six carbon atoms.

2. A lubricating composition comprising a major amount of a hydrocarbon oil and a. minor amount of the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulfide with an alleviated cyclohexanol in which substantially all of the alkyl groups have less than four carbon atoms.

3. A lubricating composition comprising a major amount of mineral lubricating oil and aminor amount of the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulflde with a methyl-cyclohexanol.

4. A lubricating composition comprising a major amount of mineral lubricating oil and a minor amount of the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulflde with an amyl-cyclohexanol.

5. A lubricating composition comprising a major amount of mineral lubricating oil and from about .1% to about 4% of the zinc salt of the reaction product obtained by reacting one mole of phosphorus pentasulflde with approximately five moles of methyl-cyclohexanol.

6. A lubricating composition comprising a major proportion of mineral lubricating oil and from about .1% to about 4% of the zinc salt of di (methylcyclohexyl) dithiophosphate.

7. A composition of matter for use as an addition agent in lubricants comprising an oil base and the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulfide with a methyl-cyclohexanol.

8. A corrosion-inhibiting composition comprising an oil vehicle and in solution therein an effective amount of a product obtained by reacting together zinc oxide, methyl cyclohexanol and phosphorus pentasulflde.

9. A lubricating composition comprising a major proportion of lubricating oil suitable for use .anol in which substantially all of the alkyii groups have less than six carbon atoms.

10. A lubricating composition comprising a major amount of mineral lubricating oil and a minor amount of the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulfide with a propyl-cyclohexanol.

11. A lubricating composition comprising a major amount of mineral lubricating oil and from about .1% to about 4% of the zinc salt of the reaction product obtained by reacting one mole of phosphorus pentasulfide with approximately five moles of an alkylated cyclohexanol in which substantially all of the alkyl groups have less than six carbon atoms.

12. A lubricating composition comprising a major proportion of mineral lubricating oil and from about .1% to about 4% of the zinc salt of a di(alky1cyclohexyl)dithiophosphate in which substantially all 01 the alkyl groups have less than six carbon atoms.

13. A composition of matter for use as an addition agent in lubricants comprising an oil base and the zinc salt of an acidic reaction product obtained by reacting phosphorus pentasulfide with an alkylated cyclohexanol in which substantially all of the alkyl groups have less than six carbon atoms.

14. A corrosion-inhibiting composition comprising an oil vehicle and in solution therein an efiective amount of a product obtained by reacting together zinc oxide, phosphorus pentasulfide and an alkylated cyclohexanol in which substantially all of the alkyl groups have less than six carbon atoms.

PETER A. ASSEFF. 

